The use of antipsychotics has become increasingly prevalent in children and adolescents despite the paucity of evidence suggesting efficacy and safety. In a recent study evaluating antipsychotic use in the Texas Medicaid child and adolescent population, prevalence rates for total antipsychotic use increased 160% over a five-year period (1996 to 2000), with all of this increase attributable to atypical antipsychotics (+494%). The purpose of this study is to examine the recent trends (1994 to 2001) of antipsychotic use and effects on health care outcomes in children and adolescents. A total of five Medicaid states, geographically diverse, will be used to collect data. Prevalence is defined as the number of children and adolescents with at least one Medicaid prescription claim for an antipsychotic, regardless of subclass, per 1,000 enrollees. Total antipsychotic, typical antipsychotic and atypical antipsychotic prevalence rates will be determined. Age-specific and gender-specific prevalence rates will also be calculated. Documented diagnoses, duration of antipsychotic therapy, and concomitant psychotropic medication use will be assessed. Using Medicaid service utilization databases, the study will evaluate the documented use of antipsychotics and identify the primary sources of antipsychotic prescribing. Secondary analyses to be included in this study will assess total Medicaid expenditures, including drug costs and health care service utilization. These analyses will examine total antipsychotic, typical antipsychotic, and atypical antipsychotic Medicaid expenditures.